This invention relates to a multi-purpose clutch assembly for connecting full-speed power to dead load, and more particularly, to such a clutch assembly of the friction-type which may be used to connect power to virtually any load to be driven. The invention is especially suitable for transmitting power from the power-take-off of a two-wheel drive vehicle to an auxiliary drive axle for the vehicle to thereby convert the two-wheel drive vehicle to all-wheel drive.
The clutch assembly of the invention is capable of use in a wide variety of applications where power delivery to an outside demand is required, such as industrial, materials handling, agricultural, marine and transportation applications. Typical applications in addition to transmitting power from the power-take-off of a two-wheel drive vehicle to an auxiliary drive axle for the vehicle include use as a drive unit to creep drive a ditch digging machine, and as a drive unit to drive a high volume, high torque hydraulic pump.
For some years, drive attachments have been available for converting two-wheel drive vehicles to four-wheel drive, especially for use with tractors. Such drive attachments have commonly taken the form of a conversion unit for use with a conventional farm tractor having only two-wheel drive. An example of such a conversion unit may be found in U.S. Pat. No. 2,855,063 to Steinke and Erickson. Such drive attachments enable a two-wheel drive tractor, for instance, to be converted to four-wheel drive which is particularly advantageous for certain ground traction and planting conditions encountered in farming.
One of the disadvantages of conventional drive attachments for such applications is that the vehicle must be at a standstill in order to shift it from two-wheel to four-wheel drive. Yet, it is often desirable for a farmer or other vehicle driver to be able to shift from two-wheel drive to four-wheel drive, and vice versa, instantly while the tractor is in motion. For example, sometimes an abrupt change in farming soil or road conditions makes it desirable for the farmer to be able to quickly shift from two to four-wheel drive without having to stop the tractor.
A primary object of the invention is to provide a clutch assembly for quickly shifting a vehicle from two-wheel to four-wheel drive, which provides quick and positive clutching action at fingertip control of the driver of the vehicle. An allied object of the invention is to provide such a clutch assembly which provides "on-the-go" engagement of all-wheel drive for the vehicle when desired, so that the driver may engage the clutch while the vehicle is in motion to cause the auxiliary wheels to begin pulling immediately. Still another object of the invention is to provide such a clutch assembly which enables the vehicle, when engaged in all-wheel drive, to move quickly and securely on wet or other poor traction type soils.
An allied object of the invention is to provide such a clutch assembly which transmits high torque from the power-take-off of the vehicle to an auxiliary drive axle for the vehicle to thereby provide better vehicle wheel traction and increased vehicle pulling power. Another object of the invention is to provide such a clutch assembly which is fuel efficient, increases vehicle tire wear, and extends the vehicle life beyond that of conventional clutches.
Another object of the invention is to provide a clutch assembly which is compact and light in weight, yet which is capable of transmitting high-power loads from the main drive of a vehicle to the auxiliary wheels in just a fraction of a second. An allied object is to provide such a clutch assembly which, when the vehicle is engaged in all-wheel drive, lends assurance that each of the vehicle wheels maintains drive at all times. Still another object of the invention is to provide such a clutch assembly which may be compactly secured to a vehicle such as a tractor so as to provide sufficient mid-tractor clearance that the tractor may be operated over rough terrain without damaging the auxiliary wheel driveline. Still another object of the invention is to provide such a clutch assembly as a totally sealed unit, eliminating conventional maintenance requirements.
Certain preferred structures in accordance with the invention have been described and illustrated. It will be apparent to those skilled in the art that various changes and modifications may be made therein within the spirit and scope of the invention. It is intended that such changes and modifications be included within the scope of the appended claims.